U.S. patent application number 10/975501 was filed with the patent office on 2005-07-21 for method of chemically mechanically polishing substrates.
Invention is credited to Scott, Brandon Shane.
Application Number | 20050159085 10/975501 |
Document ID | / |
Family ID | 34752915 |
Filed Date | 2005-07-21 |
United States Patent
Application |
20050159085 |
Kind Code |
A1 |
Scott, Brandon Shane |
July 21, 2005 |
Method of chemically mechanically polishing substrates
Abstract
The present invention relates to a method of polishing a
substrate. The invention more particularly relates to the chemical
mechanical polishing of a substrate enhanced by the addition of a
refractory metal. A method according to the present disclosure
comprises using an oxidizing agent, a refractory metal suspended in
a liquid carrier with an optional abrasive to polish a
metal-containing substrate. The refractory metal agent can be
dissolved ions, particulate material, or both. The present
invention further relates to a method of cleaning a polished
substrate.
Inventors: |
Scott, Brandon Shane;
(Hayward, CA) |
Correspondence
Address: |
MORGAN LEWIS & BOCKIUS LLP
1111 PENNSYLVANIA AVENUE NW
WASHINGTON
DC
20004
US
|
Family ID: |
34752915 |
Appl. No.: |
10/975501 |
Filed: |
October 29, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60515450 |
Oct 30, 2003 |
|
|
|
Current U.S.
Class: |
451/41 ;
257/E21.304; 451/60 |
Current CPC
Class: |
C09G 1/02 20130101; H01L
21/02074 20130101; H01L 21/3212 20130101; B24B 37/044 20130101 |
Class at
Publication: |
451/041 ;
451/060 |
International
Class: |
B24B 001/00 |
Claims
1. A method for chemically polishing mechanically polishing a
metal-containing substrate comprising: providing a substrate having
a surface comprising a metal, a metal-containing compound, or both;
providing a polishing composition comprising dissolved
tantalum-containing ions and a liquid carrier; and contacting the
substrate surface with the polishing composition under conditions
suitable to chemically mechanically polish the substrate
surface.
2. The method of claim 1 wherein the composition comprises 0.1 ppm
to 2% by weight of dissolved tantalum.
3. The method of claim 1 wherein the composition comprises 0.5 ppm
to about 50 ppm of dissolved tantalum.
4. The method of claim 1 wherein the composition comprises 51 ppm
to about 500 ppm of dissolved tantalum.
5. The method of claim 1 wherein the composition further comprises
an oxidizer.
6. The method of claim 1 wherein the composition further comprises
an abrasive.
7. The method of claim 1 wherein the substrate comprises
copper.
8. A method for chemically polishing mechanically polishing a
metal-containing substrate comprising: providing a substrate having
a surface comprising a metal, a metal-containing compound, or both;
providing a polishing composition comprising dissolved refractory
metal-containing contacting the substrate surface with the
polishing composition under conditions suitable to chemically
mechanically polish the substrate surface.
9. The method of claim 8 wherein the composition comprises 0.1 ppm
to 2% by weight of dissolved refractory metal-containing ions,
wherein the refractory metal is molybdenum, rhenium, niobium,
molybdenum or combinations thereof.
10. The method of claim 9 wherein the composition comprises 0.5 ppm
to about 50 ppm of refractory metal-containing ions.
11. The method of claim 9 wherein the composition comprises 51 ppm
to about 500 ppm of dissolved tantalum.
12. The method of claim 9 wherein the composition further comprises
an oxidizer.
13. The method of claim 9 wherein the composition further comprises
an abrasive.
14. The method of claim 9 wherein the substrate comprises
copper.
15. A method for chemically polishing mechanically polishing a
metal-containing substrate comprising: providing a substrate having
a surface comprising a metal, a metal-containing compound, or both;
providing a polishing composition comprising dissolved
titanium-containing ions and a liquid carrier; and contacting the
substrate surface with the polishing composition under conditions
suitable to chemically mechanically polish the substrate
surface.
16. The method of claim 15 wherein the composition comprises 0.1
ppm to 2% by weight of dissolved titanium.
17. The method of claim 15 wherein the composition comprises 0.5
ppm to about 50 ppm of dissolved titanium.
18. The method of claim 15 wherein the composition comprises 51 ppm
to about 500 ppm of dissolved titanium.
19. The method of claim 15 wherein the composition further
comprises an oxidizer.
20. The method of claim 15 wherein the composition further
comprises an abrasive.
21. The method of claim 15 wherein the substrate comprises
copper.
22. A method for chemically polishing mechanically polishing a
metal-containing substrate comprising: providing a substrate having
a surface comprising a metal, a metal-containing compound, or both;
providing a polishing composition comprising tantalum-containing
particles and a liquid carrier; and contacting the substrate
surface with the polishing composition under conditions suitable to
chemically mechanically polish the substrate surface.
23. The method of claim 22 wherein the tantalum-containing
particles comprises tantalum nitride, tantalum oxynitrides, or
both.
24. The method of claim 22 wherein the tantalum-containing
particles comprises tantalum carbide, tantalum fluoride, or
both.
25. The method of claim 22 wherein the tantalum-containing
particles comprises a tantalum oxide.
26. The method of claim 22 wherein the composition further
comprises an oxidizer.
27. The method of claim 22 wherein the composition further
comprises an abrasive that does not comprise tantalum.
28. The method of claim 22 wherein the substrate comprises
copper.
29. A method for chemically polishing mechanically polishing a
metal-containing substrate comprising: providing a substrate having
a surface comprising a metal, a metal-containing compound, or both;
providing a polishing composition comprising tungsten-containing
particles, wherein at least a portion of the tungsten is not
tungsten carbide, and a liquid carrier; and contacting the
substrate surface with the polishing composition under conditions
suitable to chemically mechanically polish the substrate
surface.
30. The method of claim 29 wherein the tungsten-containing
particles comprises tungsten nitride, tungsten oxynitride, or
both.
31. The method of claim 29 wherein the tungsten-containing
particles comprises tungsten oxide, tungsten fluoride, or both.
32. The method of claim 29 wherein the composition further
comprises an oxidizer.
33. The method of claim 29 wherein the composition further
comprises an abrasive that does not comprise tungsten.
34. The method of claim 29 wherein the substrate comprises
copper.
35. A method for chemically polishing mechanically polishing a
metal-containing substrate comprising: providing a substrate having
a surface comprising a metal, a metal-containing compound, or both;
providing a polishing composition comprising
refractory-metal-containing particles and a liquid carrier, wherein
the refractory metal is molybdenum, rhenium, niobium, molybdenum or
combinations thereof; and contacting the substrate surface with the
polishing composition under conditions suitable to chemically
mechanically polish the substrate surface.
36. The method of claim 35 wherein the refractory-metal-containing
particles comprises refractory-metal-nitride,
refractory-metal-oxynitride- , or both.
37. The method of claim 35 wherein the refractory-metal-containing
particles comprises refractory-metal-oxide,
refractory-metal-carbide, refractory-metal-fluoride, or any
combination thereof.
38. The method of claim 35 wherein the composition further
comprises an oxidizer.
39. The method of claim 35 wherein the composition further
comprises an abrasive that does not comprise a refractory
metal.
40. The method of claim 35 wherein the substrate comprises
copper.
41. A method for chemically polishing mechanically polishing a
metal-containing substrate comprising: providing a substrate having
a surface comprising a metal, a metal-containing compound, or both;
providing a polishing composition comprising titanium-containing
particles and a liquid carrier, wherein at least a portion of the
titanium is not a titanium oxide; and contacting the substrate
surface with the polishing composition under conditions suitable to
chemically mechanically polish the substrate surface.
42. The method of claim 41 wherein the titanium-containing
particles comprises titanium-nitride, titanium-oxynitride, or
both.
43. The method of claim 41 wherein the titanium-containing
particles comprises titanium-carbide, titanium-fluoride, or any
combination thereof.
44. The method of claim 41 wherein the composition further
comprises an oxidizer.
45. The method of claim 41 wherein the composition further
comprises an abrasive that does not comprise titanium.
46. The method of claim 41 wherein the substrate comprises
copper.
47. A method for chemically polishing mechanically polishing a
metal-containing substrate comprising: providing a substrate having
a surface comprising a metal, a metal-containing compound, or both;
providing a polishing composition comprising
lanthanide-metal-containing particles and a liquid carrier; and
contacting the substrate surface with the polishing composition
under conditions suitable to chemically mechanically polish the
substrate surface.
48. The method of claim 47 wherein the lanthanide-metal-containing
particles comprises a nitride, an oxynitride, or both, of
lanthanum, ytterbium, lutetium, or combinations thereof.
49. The method of claim 47 wherein the lanthanide-metal-containing
particles comprises a carbide, a fluoride, an oxide, or
combinations thereof, of lanthanum, ytterbium, lutetium, or
combinations thereof.
50. The method of claim 47 wherein the composition further
comprises an oxidizer.
51. The method of claim 47 wherein the composition further
comprises an abrasive that does not comprise titanium.
52. A method for chemically polishing mechanically polishing a
metal-containing substrate comprising: providing a substrate having
a surface comprising a metal, a metal-containing compound, or both;
providing a polishing composition comprising rare-earth-containing
particles and a liquid carrier, wherein the rare earth comprises
cerium, praseodymium, or combinations thereof, and wherein at least
a portion of the rare earth is not a rare earth oxide; and
contacting the substrate surface with the polishing composition
under conditions suitable to chemically mechanically polish the
substrate surface.
53. The method of claim 47 wherein the rare-earth-metal-containing
particles comprises a nitride, an oxynitride, or both, of cerium,
praseodymium, or combinations thereof.
54. The method of claim 47 wherein the composition further
comprises an oxidizer, and wherein the rare-earth-metal-containing
particles are mixed at point of use with the oxidizer.
55. A method of cleaning a metal-containing substrate that had
previously undergone a polishing process comprising the step of
contacting the polished metal-containing substrate with a
composition comprising an oxidizing agent, a dissolved refractory
metal-containing ion, and a liquid carrier at a temperature and for
a time sufficient to clean the polished metal-containing
substrate.
56. A method of cleaning a metal-containing substrate that had
previously undergone an etching process, and having organometallic
etch residue thereon, comprising the step of contacting the etched
metal-containing substrate with a composition comprising an
oxidizing agent, a dissolved refractory metal-containing ion, and a
liquid carrier at a temperature and for a time sufficient to clean
the polished metal-containing substrate.
Description
FIELD OF THE INVENTION
[0001] The invention relates to compositions and methods for
chemical-mechanical polishing/planarization and/or post-CMP
cleaning of metal-containing substrates with a composition
containing an oxidizer and a refractory metal, and more
particularly to compositions and methods for chemical-mechanical
polishing/planarization and/or post-CMP cleaning of
copper-containing substrates used in integrated circuit
manufacture.
BACKGROUND OF THE INVENTION
[0002] Compositions and methods for planarizing or polishing the
surface of a substrate are well known in the art. Polishing
compositions (i.e., polishing slurries) typically contain an
abrasive material in an aqueous solution and are applied to a
surface by contacting the surface with a polishing pad saturated
with the slurry composition. Typical abrasive materials include
silicon dioxide, cerium oxide, aluminum oxide, zirconium oxide, and
tin oxide. U.S. Pat. No. 5,527,423, for example, describes a method
for chemically-mechanically polishing a metal layer by contacting
the surface with a polishing slurry comprising high purity fine
metal oxide particles in an aqueous medium. Alternatively, the
abrasive material may be incorporated in to the polishing pad. U.S.
Pat. No. 5,489,233 discloses the use of polishing pads having a
surface texture or pattern, and U.S. Pat. No. 5,958,794 discloses a
fixed abrasive polishing pad.
[0003] Conventional polishing systems and polishing methods
typically are not entirely satisfactory at planarizing
semiconductor wafers. In particular, polishing slurries and
polishing pads can have less than desirable polishing rates, and
their use in chemically-mechanically polishing semiconductor
surfaces can result in poor surface quality. Because the
performance of a semiconductor wafer is directly associated with
the planarity of its surface, it is crucial to use a polishing
method that has a high polishing efficiency, uniformity, and
removal rate and leaves a high quality polish with minimal surface
defects.
[0004] The difficulty in creating an effective polishing system for
semiconductor wafers stems from the complexity of the semiconductor
wafer. Semiconductor wafers are typically composed of a substrate,
on which a plurality of transistors has been formed. Integrated
circuits are chemically and physically connected into a substrate
by patterning regions in the substrate and layers on the substrate.
To produce an operable semiconductor wafer and to maximize the
yield, performance, and reliability of the wafer, it is desirable
to polish select surfaces of the wafer without adversely affecting
underlying structures or topography. In fact, various problems in
semiconductor fabrication can occur if the process steps are not
performed on wafer surfaces that are adequately planarized.
[0005] There have been many attempts to improve the polishing
efficiency and uniformity of conventional polishing agents, while
minimizing defectivity of the polished surface and damage to
underlying structures or topography. For example, U.S. Pat. No.
5,264,010 describes a polishing composition comprising cerium
oxide, fumed silica, and precipitated silica, which purportedly
yields an improved removal rate and polishing efficiency. U.S. Pat.
No. 5,114,437 describes a polishing composition comprising a
carrier, alumina, and a polishing accelerator selected from
chromium(III) nitrate, lanthanum nitrate, ammonium cerium nitrate,
and neodymium nitrate. U.S. Pat. No. 6,110,396 describes a
polishing composition comprising abrasive particles and dual-valent
rare earth ions in their higher valent form at acidic pH. U.S. Pat.
No. 6,143,192 describes a method of removing ruthenium or ruthenium
dioxide using a solution comprising water, ammonium cerium nitrate,
and acetic acid. Japanese Laid Open Patent Application 2000167764
describes an improved ruthenium removal rate using slurry
comprising ammonium cerium nitrate.
[0006] A need remains, however, for polishing systems and polishing
methods that will exhibit desirable planarization efficiency,
uniformity, and removal rate during the polishing and planarization
of substrates, while minimizing defectivity, such as surface
imperfections and damage to underlying structures and topography
during polishing and planarization. Specifically, a need remains to
increase the removal rate of metallic substrates when polishing.
Additionally, a need remains to make substrate polishing rates more
uniform both over time and with different structures.
[0007] The present invention seeks to provide such a polishing
system and method. These and other advantages of the present
invention will be apparent from the description of the invention
provided herein.
BRIEF SUMMARY OF THE INVENTION
[0008] In another embodiment, the invention provides a method of
polishing a substrate comprising (i) contacting a substrate
comprising at least one metal and/or metal compound thereon with a
polishing composition comprising dissolved refractory metal ions
and a liquid carrier under conditions wherein at least a portion of
the metal and/or metal compound is removed from the substrate by
chemical mechanical polishing. The refractory metal can be
molybdenum, tungsten, rhenium, niobium, tantalum, molybdenum and
combinations thereof. In alternate embodiments, the refractory
metal can be replaced by titanium. The preferred refractory metal
is tantalum. In preferred embodiments the composition further
comprises an oxidizer. In one embodiment the composition comprises
0.1 ppm to 2% by weight of dissolved refractory metal ions. In one
preferred embodiment, the composition comprises about 0.1 ppm to
about 50 ppm of dissolved refractory metal ions. In another
preferred embodiment, the composition comprises about 51 ppm to
about 500 ppm of dissolved refractory metal ions. While refractory
metals is on occasion (even typically) a material removed from the
substrate, the invention specifically excludes embodiments where
the refractory metals from the substrate is the sole source of
refractory metals in the polishing composition, as the uneven
amount and distribution of the refractory metals resulting
therefrom provides uneven, and therefore undesired performance.
[0009] In another embodiment, the invention provides a method of
polishing a substrate comprising (i) contacting a substrate
comprising at least one metal and/or metal compound thereon with a
liquid carrier and a polishing pad comprising
refractory-metal-containing particles under conditions wherein at
least a portion of the metal and/or metal compound is removed from
the substrate by chemical mechanical polishing. The
refractory-metal-containing particles can be any substance
containing molybdenum, tungsten, rhenium, niobium, tantalum,
molybdenum and combinations thereof. In alternate embodiments, the
refractory metal can be replaced by titanium. In alternate
embodiments, the refractory metal can be replaced by lanthanides.
In alternate embodiments, the refractory metal can be replaced by
rare-earth-metals. The preferred refractory metal is tantalum. In
one preferred embodiment, the composition comprises particles that
comprise or consist essentially of refractory-metal-nitrid- e. In
an alternate embodiment, the composition comprises particles that
comprise or consist essentially of refractory-metal-oxynitrides. In
an alternate embodiment, the composition comprises particles that
comprise or consist essentially of refractory-metal-carbide. In an
alternate embodiment, the composition comprises particles that
comprise or consist essentially of refractory-metal-fluoride. In an
alternate but less preferred embodiment, the composition comprises
particles that comprise or consist essentially of
refractory-metal-oxide. While the particulate refractory-metal
material may be the sole abrasive, it is preferred that the
polishing composition further comprise at least one of alumina (for
example but not limited to colloidal, fumed, alpha, gamma, and the
like), silica (for example but not limited to colloidal or fumed),
titania and/or mixed titanium oxides, ceria and/or mixed cerium
oxides, zirconia, germania, magnesia, co-formed products thereof,
and any combinations thereof. Generally, if the
refractory-metal-containing particles are to also function as a
primary abrasive, it is preferred that the polishing composition
comprise between about 0.1% to 25%, for example between about 0.5%
to 7%, by weight, compared to the weight of the liquid portion of
the composition, of refractory-metal-containing particles.
Generally, if the composition comprises another primary abrasive
material such as is listed above, the amount of
refractory-metal-containing particles can be greatly reduced. The
amount of refractory-metal-containing particles can then range for
example from about 10 ppm to about 10%, alternately from about 50
ppm to about 1%, by weight compared to the weight of the liquid
portion of the composition. It is preferred that the size of the
refractory-metal-containing particles be within about 150% to about
5%, for example 80% to 20%, of the size (diameter) of the other
primary abrasive. In alternate embodiments, some or all of the
refractory-metal-containing particles can be affixed to or imbedded
in a polishing pad. In alternate embodiments, some or all of the
titanium and/or lanthanides-containing particles can be affixed to
or imbedded in a polishing pad.
[0010] Any of the above embodiments can be combined with any other
embodiment(s).
[0011] In preferred embodiments, the substrate comprises copper
and/or copper alloys.
[0012] In preferred embodiments the polishing compositions further
comprise oxidizers.
[0013] For compositions wherein the particulate matter may have
unacceptable solubility over long-term storage, a slurry containing
particles of the above listed embodiments may be stored in a
separate slurry and be mixed at point of use to form a polishing
slurry.
[0014] The invention also encompasses a method of cleaning a
metal-containing substrate that had previously undergone a
polishing process comprising the step of contacting the polished
metal-containing substrate with a composition comprising an
oxidizing agent; a dissolved refractory metal-containing ion, a
dissolved titanium-containing ion, or both; and a liquid carrier,
at a temperature and for a time sufficient to clean the polished
metal-containing substrate.
[0015] The invention also encompasses a method of cleaning a
metal-containing substrate that had previously undergone an etching
process, and having organometallic etch residue thereon, comprising
the step of contacting the etched metal-containing substrate with a
composition comprising an oxidizing agent, a dissolved refractory
metal-containing ion, a dissolved titanium-containing ion, or both;
and a liquid carrier, at a temperature and for a time sufficient to
clean the polished metal-containing substrate.
DETAILED EMBODIMENTS OF THE INVENTION
[0016] The invention is directed to a method of polishing a
substrate using a system comprising an abrasive and/or polishing
pad, an oxidizer, a refractory metal agent and a carrier. The
abrasive (when present and suspended in the liquid carrier),
refractory metal agent, an oxidizer, and liquid carrier, as well as
any other components suspended in the liquid carrier, form the
polishing composition of the polish system.
[0017] The invention provides a method of polishing a substrate
comprising (i) contacting a substrate comprising at least one metal
and/or metal compound thereon with a polishing composition
comprising dissolved tantalum and a liquid carrier under conditions
wherein at least a portion of the metal and/or metal compound is
removed from the substrate by chemical mechanical polishing. In
preferred embodiments the composition further comprises an
oxidizer. In one embodiment the composition comprises 0.1 ppm to 2%
by weight of dissolved tantalum. In one preferred embodiment, the
composition comprises about 0.1 ppm to about 50 ppm of dissolved
tantalum. In another preferred embodiment, the composition
comprises about 51 ppm to about 500 ppm of dissolved refractory
metal ions. While tantalum is on occasion (even typically) a
material removed from the substrate, the invention specifically
excludes embodiments where the tantalum from the substrate is the
sole source of tantalum in the polishing composition, as the uneven
amount and distribution of the tantalum resulting therefrom
provides uneven, and therefore undesired performance.
[0018] In another embodiment, the invention provides a method of
polishing a substrate comprising (i) contacting a substrate
comprising at least one metal and/or metal compound thereon with a
polishing composition comprising dissolved refractory metal ions
and a liquid carrier under conditions wherein at least a portion of
the metal and/or metal compound is removed from the substrate by
chemical mechanical polishing. The refractory metal can be
molybdenum, tungsten, rhenium, niobium, tantalum, molybdenum and
combinations thereof. In preferred embodiments the composition
further comprises an oxidizer. In one embodiment the composition
comprises 0.1 ppm to 2% by weight of dissolved refractory metal
ions. In one preferred embodiment, the composition comprises about
0.1 ppm to about 50 ppm of dissolved refractory metal ions. In
another preferred embodiment, the composition comprises about 51
ppm to about 500 ppm of dissolved refractory metal ions. While
refractory metals is on occasion (even typically) a material
removed from the substrate, the invention specifically excludes
embodiments where the refractory metals from the substrate is the
sole source of refractory metals in the polishing composition, as
the uneven amount and distribution of the refractory metals
resulting therefrom provides uneven, and therefore undesired
performance.
[0019] The invention provides a method of polishing a substrate
comprising (i) contacting a substrate comprising at least one metal
and/or metal compound thereon with a polishing composition
comprising dissolved titanium and a liquid carrier under conditions
wherein at least a portion of the metal and/or metal compound is
removed from the substrate by chemical mechanical polishing. In
preferred embodiments the composition further comprises an
oxidizer. In one embodiment the composition comprises 0.1 ppm to 2%
by weight of dissolved titanium. In one preferred embodiment, the
composition comprises about 0.1 ppm to about 50 ppm of dissolved
titanium. In another preferred embodiment, the composition
comprises about 51 ppm to about 500 ppm of dissolved titanium ions.
While titanium is on occasion (even typically) a material removed
from the substrate, the invention specifically excludes embodiments
where the titanium from the substrate is the sole source of
titanium ions in the polishing composition, as the uneven amount
and distribution of the tantalum resulting therefrom provides
uneven, and therefore undesired performance. Additionally, the
invention excludes embodiments where a small amount of dissolved
titanium is present where the source of the titanium is titanium
oxides, as this amount is considered to be too small to be
useful.
[0020] In another embodiment, the invention provides a method of
polishing a substrate comprising (i) contacting a substrate
comprising at least one metal and/or metal compound thereon with a
polishing composition comprising tantalum-containing particles and
a liquid carrier under conditions wherein at least a portion of the
metal and/or metal compound is removed from the substrate by
chemical mechanical polishing. The particles can be homogenous or
heterogenous. In one preferred embodiment, the composition
comprises particles that comprise or consist essentially of
tantalum nitride. In an alternate embodiment, the composition
comprises particles that comprise or consist essentially of
tantalum oxynitrides. In an alternate embodiment, the composition
comprises particles that comprise or consist essentially of
tantalum carbide. In an alternate embodiment, the composition
comprises particles that comprise or consist essentially of
tantalum fluoride. In an alternate but less preferred embodiment,
the composition comprises particles that comprise or consist
essentially of tantalum oxide. While the particulate tantalum
material may be the sole abrasive, it is preferred that the
polishing composition further comprise at least one of alumina (for
example but not limited to colloidal, filmed, alpha, gamma, and the
like), silica (for example but not limited to colloidal or fumed),
titania and/or mixed titanium oxides, ceria and/or mixed cerium
oxides, zirconia, germania, magnesia, co-formed products thereof,
and any combinations thereof. Generally, if the tantalum-containing
particles are to also function as a primary abrasive, it is
preferred that the polishing composition comprise between about
0.1% to 25%, for example between about 0.5% to 7%, by weight,
compared to the weight of the liquid portion of the composition, of
tantalum-containing particles. Generally, if the composition
comprises another primary abrasive material such as is listed
above, the amount of tantalum-containing particles can be greatly
reduced. The amount of tantalum-containing particles can then range
for example from about 10 ppm to about 10%, alternately from about
50 ppm to about 1%, by weight compared to the weight of the liquid
portion of the composition. It is preferred that the size of the
tantalum-containing particles be within about 150% to about 5%, for
example 80% to 20%, of the size (diameter) of the other primary
abrasive.
[0021] In another embodiment, the invention provides a method of
polishing a substrate comprising (i) contacting a substrate
comprising at least one metal and/or metal compound thereon with a
liquid carrier and a polishing pad comprising tungsten-containing
particles under conditions wherein at least a portion of the metal
and/or metal compound is removed from the substrate by chemical
mechanical polishing. In one preferred embodiment, the composition
comprises particles that comprise or consist essentially of
tungsten nitride. In an alternate embodiment, the composition
comprises particles that comprise or consist essentially of
tungsten oxynitrides. In an alternate embodiment, the composition
comprises particles that comprise or consist essentially of
tungsten carbide. In an alternate embodiment, the composition
comprises particles that comprise or consist essentially of
tungsten fluoride. In an alternate but less preferred embodiment,
the composition comprises particles that comprise or consist
essentially of tungsten oxide. While the particulate tungsten
material may be the sole abrasive, it is preferred that the
polishing composition further comprise at least one of alumina (for
example but not limited to colloidal, fumed, alpha, gamma, and the
like), silica (for example but not limited to colloidal or fumed),
titania and/or mixed titanium oxides, ceria and/or mixed cerium
oxides, zirconia, germania, magnesia, co-formed products thereof,
and any combinations thereof. Generally, if the tungsten-containing
particles are to also function as a primary abrasive, it is
preferred that the polishing composition comprise between about
0.1% to 25%, for example between about 0.5% to 7%, by weight,
compared to the weight of the liquid portion of the composition, of
tungsten-containing particles. Generally, if the composition
comprises another primary abrasive material such as is listed
above, the amount of tungsten-containing particles can be greatly
reduced. The amount of tungsten-containing particles can then range
for example from about 10 ppm to about 10%, alternately from about
50 ppm to about 1%, by weight compared to the weight of the liquid
portion of the composition. It is preferred that the size of the
tungsten-containing particles be within about 150% to about 5%, for
example 80% to 20%, of the size (diameter) of the other primary
abrasive.
[0022] In another embodiment, the invention provides a method of
polishing a substrate comprising (i) contacting a substrate
comprising at least one metal and/or metal compound thereon with a
liquid carrier and a polishing pad comprising
refractory-metal-containing particles under conditions wherein at
least a portion of the metal and/or metal compound is removed from
the substrate by chemical mechanical polishing. The
refractory-metal-containing particles can be any substance
containing molybdenum, tungsten, rhenium, niobium, tantalum,
molybdenum and combinations thereof. In one preferred embodiment,
the composition comprises particles that comprise or consist
essentially of refractory-metal-nitride. In an alternate
embodiment, the composition comprises particles that comprise or
consist essentially of refractory-metal-oxynitrides. In an
alternate embodiment, the composition comprises particles that
comprise or consist essentially of refractory-metal-carbide. In an
alternate embodiment, the composition comprises particles that
comprise or consist essentially of refractory-metal-fluoride. In an
alternate but less preferred embodiment, the composition comprises
particles that comprise or consist essentially of
refractory-metal-oxide. While the particulate refractory-metal
material may be the sole abrasive, it is preferred that the
polishing composition further comprise at least one of alumina (for
example but not limited to colloidal, fumed, alpha, gamma, and the
like), silica (for example but not limited to colloidal or fumed),
titania and/or mixed titanium oxides, ceria and/or mixed cerium
oxides, zirconia, germania, magnesia, co-formed products thereof,
and any combinations thereof. Generally, if the
refractory-metal-containing particles are to also function as a
primary abrasive, it is preferred that the polishing composition
comprise between about 0.1% to 25%, for example between about 0.5%
to 7%, by weight, compared to the weight of the liquid portion of
the composition, of refractory-metal-containing particles.
Generally, if the composition comprises another primary abrasive
material such as is listed above, the amount of
refractory-metal-containing particles can be greatly reduced. The
amount of refractory-metal-containing particles can then range for
example from about 10 ppm to about 10%, alternately from about 50
ppm to about 1%, by weight compared to the weight of the liquid
portion of the composition. It is preferred that the size of the
refractory-metal-containing particles be within about 150% to about
5%, for example 80% to 20%, of the size (diameter) of the other
primary abrasive.
[0023] In another embodiment, the invention provides a method of
polishing a substrate comprising (i) contacting a substrate
comprising at least one metal and/or metal compound thereon with a
liquid carrier and a polishing pad comprising titanium-containing
particles under conditions wherein at least a portion of the metal
and/or metal compound is removed from the substrate by chemical
mechanical polishing. In one preferred embodiment, the composition
comprises particles that comprise or consist essentially of
titanium nitride. In an alternate embodiment, the composition
comprises particles that comprise or consist essentially of
titanium oxynitrides. In an alternate embodiment, the composition
comprises particles that comprise or consist essentially of
titanium carbide. In an alternate embodiment, the composition
comprises particles that comprise or consist essentially of
titanium fluoride. While the particulate titanium material may be
the sole abrasive, it is preferred that the polishing composition
further comprise at least one of alumina (for example but not
limited to colloidal, fumed, alpha, gamma, and the like), silica
(for example but not limited to colloidal or fumed), titania and/or
mixed titanium oxides, ceria and/or mixed cerium oxides, zirconia,
germania, magnesia, co-formed products thereof, and any
combinations thereof. Generally, if the titanium-containing
particles are to also function as a primary abrasive, it is
preferred that the polishing composition comprise between about
0.1% to 25%, for example between about 0.5% to 7%, by weight,
compared to the weight of the liquid portion of the composition, of
titanium-containing particles. Generally, if the composition
comprises another primary abrasive material such as is listed
above, the amount of titanium-containing particles (excluding
titanium oxides) can be greatly reduced. The amount of
titanium-containing particles (excluding titanium oxides) can then
range for example from about 10 ppm to about 10%, alternately from
about 50 ppm to about 1%, by weight compared to the weight of the
liquid portion of the composition. It is preferred that the size of
the titanium-containing particles (excluding titanium oxides) be
within about 150% to about 5%, for example 80% to 20%, of the size
(diameter) of the other primary abrasive.
[0024] In another embodiment, the invention provides a method of
polishing a substrate comprising (i) contacting a substrate
comprising at least one metal and/or metal compound thereon with a
liquid carrier and a polishing pad comprising
lanthanide-metal-containing particles under conditions wherein at
least a portion of the metal and/or metal compound is removed from
the substrate by chemical mechanical polishing. The
lanthanide-metal-containing particles can be any substance
containing for example lanthanum, ytterbium or lutetium, and
combinations thereof. In one preferred embodiment, the composition
comprises particles that comprise or consist essentially of
lanthanide-metal-nitride. In an alternate embodiment, the
composition comprises particles that comprise or consist
essentially of lanthanide-metal-oxynitrides. In an alternate
embodiment, the composition comprises particles that comprise or
consist essentially of lanthanide-metal-carbide. In an alternate
embodiment, the composition comprises particles that comprise or
consist essentially of lanthanide-metal-fluoride. In an alternate
but less preferred embodiment, the composition comprises particles
that comprise or consist essentially of lanthanide-metal-oxide.
While the particulate lanthanide-metal material may be the sole
abrasive, it is preferred that the polishing composition further
comprise at least one of alumina (for example but not limited to
colloidal, fumed, alpha, gamma, and the like), silica (for example
but not limited to colloidal or fumed), titania and/or mixed
titanium oxides, ceria and/or mixed cerium oxides, zirconia,
germania, magnesia, co-formed products thereof, and any
combinations thereof. Generally, if the lanthanide-metal-containing
particles are to also function as a primary abrasive, it is
preferred that the polishing composition comprise between about
0.1% to 25%, for example between about 0.5% to 7%, by weight,
compared to the weight of the liquid portion of the composition, of
lanthanide-metal-containing particles. Generally, if the
composition comprises another primary abrasive material such as is
listed above, the amount of lanthanide-metal-containing particles
can be greatly reduced. The amount of
lanthanide-metal-metal-containing particles can then range for
example from about 10 ppm to about 10%, alternately from about 50
ppm to about 1%, by weight compared to the weight of the liquid
portion of the composition. It is preferred that the size of the
lanthanide-metal-containing particles be within about 150% to about
5%, for example 80% to 20%, of the size (diameter) of the other
primary abrasive.
[0025] In another embodiment, the invention provides a method of
polishing a substrate comprising (i) contacting a substrate
comprising at least one metal and/or metal compound thereon with a
liquid carrier and a polishing pad comprising
rare-earth-metal-containing particles under conditions wherein at
least a portion of the metal and/or metal compound is removed from
the substrate by chemical mechanical polishing. The
rare-earth-containing particles can be any substance containing for
example cerium, praseodymium, and combinations thereof, but not
including the rare-earth-metal-oxides. In one preferred embodiment,
the composition comprises particles that comprise or consist
essentially of rare-earth-metal-nitride. In an alternate
embodiment, the composition comprises particles that comprise or
consist essentially of rare-earth-metal-oxynitrides. In an
alternate embodiment, the composition comprises particles that
comprise or consist essentially of rare-earth-metal-carbide. In an
alternate embodiment, the composition comprises particles that
comprise or consist essentially of rare-earth-metal-fluoride. While
the particulate rare-earth-metal material may be the sole abrasive,
it is preferred that the polishing composition further comprise at
least one of alumina (for example but not limited to colloidal,
fumed, alpha, gamma, and the like), silica (for example but not
limited to colloidal or fumed), titania and/or mixed titanium
oxides, ceria and/or mixed cerium oxides, zirconia, germania,
magnesia, co-formed products thereof, and any combinations thereof.
Generally, if the rare-earth-metal-containing particles are to also
function as a primary abrasive, it is preferred that the polishing
composition comprise between about 0.1% to 25%, for example between
about 0.5% to 7%, by weight, compared to the weight of the liquid
portion of the composition, of rare-earth-metal-containing
particles. Generally, if the composition comprises another primary
abrasive material such as is listed above, the amount of
rare-earth-metal-containing particles can be greatly reduced. The
amount of rare-earth-metal-metal-containing particles can then
range for example from about 10 ppm to about 10%, alternately from
about 50 ppm to about 1%, by weight compared to the weight of the
liquid portion of the composition. It is preferred that the size of
the rare-earth-metal-containing particles be within about 150% to
about 5%, for example 80% to 20%, of the size (diameter) of the
other primary abrasive.
[0026] Any of the above embodiments can be combined with any other
embodiment(s).
[0027] In preferred embodiments, the substrate comprises copper
and/or copper alloys.
[0028] In preferred embodiments the polishing compositions further
comprise oxidizers.
[0029] One aspect of the present invention includes a composition,
e.g. used in a method for chemical mechanical polishing of metal
containing substrate, particularly of copper containing substrates,
containing: between about 0.01% and 30%, for example between about
0.5% to about 7%, by weight of an oxidizing agent based on weight
of fluid; between about 0.5 ppm to about 3% by weight of the fluid,
preferably from about 5 ppm to about 0.1%, for example from about 5
ppm to about 1500 ppm, from about 5 ppm to about 2000 ppm, from
about 1500 ppm to about 3000 ppm, from about 2500 ppm to about 3500
ppm, from about 3500 ppm to about 6000 ppm, from about 5500 ppm to
about 8000 ppm, from about 7500 ppm to about 0.1%, of a refractory
metal agent (as a solid, as dissolved ions, or both if both are
present); a liquid carrier and optionally an abrasive.
[0030] The polishing system optionally comprises an abrasive, a
polishing pad, or both. Preferably, the system comprises both an
abrasive and a polishing pad. The abrasive can be any suitable
abrasive. The abrasive can be fixed on the polishing pad and/or can
be in particulate form and suspended in the liquid carrier. The
polishing pad can be any suitable polishing pad.
[0031] The abrasive is any suitable abrasive known in the art. For
example, the abrasive particles are natural or synthetic and
include diamond (e.g., polycrystalline diamond), garnet, glass,
carborundum, metal oxide (e.g., silica, fused alumina, ceramic
alumina, chromia, and iron oxide), and the like. The abrasive
particles may be coated particle abrasives. The abrasive preferably
is a metal oxide abrasive and more preferably is selected from the
group consisting of alumina, silica, titania, ceria, zirconia,
germania, magnesia, co-formed products thereof, and combinations
thereof.
[0032] Any of the refractory-metal-containing particles containing
molybdenum, tungsten, rhenium, niobium, tantalum, molybdenum and
combinations thereof, or containing titanium, or containing
lanthanides, or containing rare-earth-metals, can be homogenous,
can be coated on another abrasive, or can be co-formed with an
abrasive material.
[0033] The particle size of the refractory-metal-containing
particles containing molybdenum, tungsten, rhenium, niobium,
tantalum, molybdenum and combinations thereof, or containing
titanium, or containing lanthanides, or containing
rare-earth-metals, can be from about 0.003 microns to about 2
microns, for example between about 0.02 microns to about 1 micron,
alternately between 0.04 microns and 0.3 microns, or alternately
between 0.05 microns and 0.14 microns. Generally, smaller amounts
are needed if smaller particles are used, as it is believed that
the recited metals within the particle interact with the substrate,
for example the copper, copper aluminum, or other, and this
interaction accelerates the polishing.
[0034] In some instances the substrate will comprise a metal such
as is includes in the claimed embodiments. Having the material in
the polishing compositions prior to polishing has several
advantages. First, the activity of the polishing composition will
be relatively un-affected by the addition of small amounts of
agent, because of solubility limitations; the phenomenon of
decreasing activity expressed as additional polishing rate per unit
weight of component of this invention in the slurry, with higher
concentrations; and or simply that the addition of material from
the substrate is only a small fraction of the material already
present in the polishing composition. Also, it is often encountered
that at the beginning of a polishing process the metals of the type
recited in various embodiments of the invention, for example
tantalum nitride, may be buried beneath for example copper, and the
presence of the components of this invention allows more uniform
polishing rates compared to rates observed before and after such
compounds on the substrate are exposed to the polishing process.
Finally, incorporating the components of this invention into a
slurry minimizes unfavorable differentials in polishing rates that
are observed spacially across a substrate surface and which in many
instances can be correlated to distance from the refractory metal
containing compound present on the surface of the substrate.
[0035] When the abrasive is both present in the system and
suspended in the liquid carrier (i.e., when the abrasive is a
component of the polishing composition), any suitable amount of
abrasive can be present in the polishing composition. Typically,
about 0.1 wt. % or more (e.g., about 0.5 wt. % or more) abrasive
will be present in the polishing composition. More typically, about
1 wt. % or more abrasive will be present in the polishing
composition. The amount of abrasive in the polishing composition
typically will not exceed about 30 wt. %, more typically will not
exceed about 20 wt. % (e.g., will not exceed about 10 wt. %).
[0036] The refractory metal agent in certain embodiments is
suspended in the liquid carrier. The refractory metal agent can be
any substance containing molybdenum, tungsten, rhenium, niobium and
tantalum and combinations thereof. Such substances include, but are
not limited to, to oxides, salts, and nitrides of molybdenum,
tungsten, rhenium, niobium and tantalum and mixtures thereof.
Examples of such substances for tantalum include tantalum, tantalum
nitrides, tantalum oxides, tantalum oxynitrides, tantalum salts and
the like, and combinations thereof. Preferably, the refractory
metal agent is a tantalum-containing substance. Any suitable amount
of the refractory metal agent can be present in the polishing
composition. A suitable amount includes 0.5 ppm to about 3% by
weight, preferably from about 5 ppm to about 0.1%, for example from
about 5 ppm to about 1500 ppm, from about 5 ppm to about 2000 ppm,
from about 1500 ppm to about 3000 ppm, from about 2500 ppm to about
3500 ppm, from about 3500 ppm to about 6000 ppm, from about 5500
ppm to about 8000 ppm, from about 7500 ppm to about 0.1% of the
refractory metal agent (dissolved or in particulate material).
[0037] A liquid carrier is used to facilitate the application of
the abrasive (when present), the refractory metal agent, and
oxidizer to the surface of a suitable substrate to be polished or
planarized. The liquid carrier can be any suitable liquid carrier.
Preferably, the liquid carrier comprises, consists essentially of,
or consists of water, more preferably deionized water.
[0038] The composition according to the invention can be used on a
metal-containing substrate, preferably a copper-containing
substrate and/or a tantalum-containing substrate (e.g., copper,
copper alloys such as Cu--Al, tantalum, tantalum nitrides, tantalum
oxynitrides, tantalum oxides, tantalum alloys, and the like, and
combinations thereof).
[0039] When used as a CMP slurry, it is preferred that the
composition contain an abrasive. However, it is envisioned that the
CMP composition may be used in conjunction with an abrasive
polishing pad (e.g., a polishing pad having abrasive particles
attached thereto or contained therein), in which case the abrasive
in the slurry may be unnecessary and therefore optional. When used
in a post-cleaning system, generally the abrasive is not
desired.
[0040] The present invention can be used in conjunction with any
suitable substrate. In particular, the present invention can be
used in conjunction with memory or rigid disks, metals (e.g., noble
metals), ILD layers, integrated circuits, semiconductor devices,
semiconductor wafers, micro-electro-mechanical systems,
ferroelectrics, magnetic heads, polymeric films, and low and high
dielectric constant films, and technical or optical glass. Suitable
substrates comprise, for example, a metal, metal oxide, metal
composite, or mixtures thereof. The substrate can comprise, consist
essentially of, or consist of any suitable metal. Suitable metals
include, for example, copper, aluminum, titanium, tungsten,
tantalum, gold, platinum, iridium, ruthenium, and combinations
(e.g., alloys or mixtures) thereof. The substrate also can
comprise, consist essentially of, or consist of any suitable metal
oxide. Suitable metal oxides include, for example, alumina, silica,
titania, ceria, zirconia, germania, magnesia, and coformed products
thereof, and mixtures thereof. In addition, the substrate can
comprise, consist essentially of, or consist of any suitable metal
composite and/or metal alloy. Suitable metal composites and metal
alloys include, for example, metal nitrides (e.g., tantalum
nitride, titanium nitride, and tungsten nitride), metal carbides
(e.g., silicon carbide and tungsten carbide), nickel-phosphorus,
alumino-borosilicate, borosilicate glass, phosphosilicate glass
(PSG), borophosphosilicate glass (BPSG)), silicon/germanium alloys,
and silicon/germanium/carbon alloys. The substrate also can
comprise, consist essentially of, or consist of any suitable
semiconductor base material. Suitable semiconductor base materials
include single-crystal silicon, poly-crystalline silicon, amorphous
silicon, silicon-on-insulator, and gallium arsenide. Glass
substrates can also be used in conjunction with the present
invention including technical glass, optical glass, and ceramics,
of various types known in the art.
[0041] The formulations are particularly useful on substrates
comprising, consisting essentially of, or consisting of copper, a
copper alloy, and/or a copper compound, and the substrate may also
contain one or more solid barrier materials as are known in the
art, such as Ta, TaN, Ti, TiN, or combinations thereof.
[0042] The present invention can be used to polish any part of a
substrate (e.g., a semiconductor device) at any stage in the
production of the substrate. For example, the present invention can
be used to polish a semiconductor device in conjunction with
shallow trench isolation (STI) processing, or in conjunction with
the formation of an interlayer dielectric.
[0043] The present invention can be used in conjunction with any
suitable component (or ingredient) known in the art for use in a
composition having the same function, for example, in polishing
compositions, oxidizing agents, catalysts, film-forming agents,
complexing agents, rheological control agents, surfactants (i.e.,
surface-active agents), polymeric stabilizers, pH-adjusters, and
other appropriate ingredients, or any combinations thereof.
[0044] Any suitable oxidizing agent can be used in conjunction with
the present invention. Suitable oxidizing agents include, for
example, oxidized halides (e.g., chlorates, bromates, iodates,
perchlorates, perbromates, periodates, fluoride-containing
compounds, and mixtures thereof, and the like). Suitable oxidizing
agents also include, for example, perboric acid, periodic acid,
periodates, perborates, percarbonates, nitrates (e.g., iron (III)
nitrate, and hydroxylamine nitrate), persulfates (e.g., ammonium
persulfate), organic peroxides such as benzoyl peroxide, inorganic
peroxides such as hydrogen peroxide, peroxyacids (e.g., peracetic
acid, perbenzoic acid, m-chloroperbenzoic acid, salts thereof,
mixtures thereof, and the like), permanganates, chromates, cerium
compounds, ferricyanides (e.g., potassium ferricyanide), mixtures
thereof, and the like. Suitable oxidizers also include
hydroxylamine, hydroxylamine derivatives, and/or salts thereof.
Examples of suitable hydroxylamine or hydroxylamine derivative
include hydroxylamine, N-methyl-hydroxylamine,
N,N-dimethyl-hydroxylamine, N-ethyl-hydroxylamine,
N,N-diethyl-hydroxylamine, hydroxylamine nitrate, hydroxylamine
sulfate, hydroxylamine phosphate. Suitable oxidizers can often be
mixtures of two or more of the above-listed oxidizers, in a range
of from about 100:1 to about 1:100.
[0045] Any suitable amount of the oxidizer can be present in the
polishing composition. Typically, about 0.01 wt. % or more (e.g.,
about 0.1 wt. % or more) oxidizer will be present in the polishing
composition. More typically, about 0.2 wt. % or more (e.g., about
0.5 wt. % or more) oxidizer will be present in the polishing
composition. The amount of oxidizer in the polishing composition
typically will not exceed about 10 wt. %, more typically will not
exceed about 5 wt. % (e.g., will not exceed about 2 wt. %).
[0046] Any suitable film-forming agent (i.e., corrosion-inhibitor)
can be used in conjunction with the present invention. Suitable
film-forming agents include, for example, heterocyclic organic
compounds (e.g., organic compounds with one or more active
functional groups, such as heterocyclic rings, particularly
nitrogen-containing heterocyclic rings), and organic or inorganic
acids and derivatives thereof (e.g. salicylic acid and/or its
derivative(s)). Suitable film-forming agents also include, for
example, benzotriazole, triazole, benzimidazole, and mixtures
thereof.]
[0047] Any suitable complexing agent (i.e., chelating agent or
selectivity enhancer) can be used in conjunction with the present
invention. Suitable complexing agents include, for example,
carbonyl compounds (e.g., acetylacetonates and the like), simple
carboxylates (e.g., acetates, aryl carboxylates, and the like),
carboxylates containing one or more hydroxyl groups (e.g.,
glycolates, lactates, gluconates, gallic acid and salts thereof,
and the like), di-, tri-, and poly-carboxylates (e.g., oxalates,
phthalates, citrates, succinates, tartrates, maleates, glycolates,
edetates such as disodium EDTA, mixtures thereof, and the like),
carboxylates containing one or more sulfonic and/or phosphonic
groups, and carboxylates, di-, tri-, or poly-alcohols (e.g.,
ethylene glycol, pyrocatechol, pyrogallol, tannic acid, and the
like), phosphate-containing compounds (e.g., phosphonium salts,
phosphonic acids, and the like), amine-containing compounds (e.g.,
amino acids, amino alcohols, di-, tri-, and poly-amines, and the
like), or mixtures thereof. The amount of chelator can range from
50 ppm to 5%. For embodiments using soluble metal ions (or
metal-containing ions) it is generally preferred to use weaker
chelators, lower concentrations, and/or no chelators, as chelators
can sheild the desired metal ions and thereby reduce the activity
of these metal ions.
[0048] Any suitable surfactant and/or rheological control agent can
be used in conjunction with the present invention, including
viscosity enhancing agents and coagulants. Suitable rheological
control agents include, for example, polymeric rheological control
agents. Moreover, suitable rheological control agents include, for
example, urethane polymers (e.g., urethane polymers with a
molecular weight greater than about 100,000 Daltons), acrylates
comprising one or more acrylic subunits (e.g., vinyl acrylates and
styrene acrylates), polymers, copolymers, and oligomers thereof,
and salts thereof. Suitable surfactants include, for example,
cationic surfactants, anionic surfactants, anionic
polyelectrolytes, nonionic surfactants, amphoteric surfactants,
fluorinated surfactants, mixtures thereof, and the like. In one
embodiment, the surfactant and/or rheological control agent can be
present in an amount between about 0.05% to 4% by weight based on
the weight of the fluid.
[0049] The composition used in conjunction with the present
invention can contain any suitable polymeric stabilizer or other
surface active dispersing agent, for example, phosphoric acid,
organic acids, tin oxides, organic phosphonates, and the like, and
mixtures thereof. Polymeric stabilizers include an amine-containing
polymer or copolymer, for example, polyethylenimine,
polyetheramine, polydiallyldimethylammoniu- m chloride
(polydadmac), and mixtures thereof. In one embodiment, the
polymeric stabilizer can be present in an amount between about
0.01% to 3% by weight based on the weight of the fluid.
[0050] The polishing composition can have any suitable pH. For
example, the polishing composition can have a pH of about 1 to
about 12 (e.g. about 2 to about 9). The actual pH of the polishing
composition will depend, in part, on the type of substrate being
polished, and in the oxidizer. Generally, the desired pH of the
composition is the same pH as is desirable in a composition not
having the component(s) of this invention when used on the
particular substrates.
[0051] As those of skill in the art will recognize, certain
compounds may perform more than one function. For example, some
compounds can function both as a chelating and an oxidizing agent
(e.g., certain ferric nitrates and the like).
[0052] The use of the terms "a" and "an" and "the" and similar
referents in the context of describing the invention (especially in
the context of the following claims) are to be construed to cover
both the singular and the plural, unless otherwise indicated herein
or clearly contradicted by context. Recitation of ranges of values
herein are merely intended to serve as a shorthand method of
referring individually to each separate value falling within the
range, unless otherwise indicated herein, and each separate value
is incorporated into the specification as if it were individually
recited herein. All methods described herein can be performed in
any suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g., "such as") provided herein, is
intended merely to better illuminate the invention and does not
pose a limitation on the scope of the invention unless otherwise
claimed. No language in the specification should be construed as
indicating any non-claimed element as essential to the practice of
the invention.
[0053] Preferred embodiments of this invention are described
herein, including the best mode known to the inventors for carrying
out the invention. Of course, variations of those preferred
embodiments will become apparent to those of ordinary skill in the
art upon reading the foregoing description. The inventors expect
skilled artisans to employ such variations as appropriate, and the
inventors intend for the invention to be practiced otherwise than
as specifically described herein. Accordingly, this invention
includes all modifications and equivalents of the subject matter
recited in the claims appended hereto as permitted by applicable
law. Moreover, any combination of the above-described elements in
all possible variations thereof is encompassed by the invention
unless otherwise indicated herein or otherwise clearly contradicted
by context.
* * * * *